Valve device



July 7, `1942.

E. A. ROCKWELL VALVE DEVI CE Original Filed Nov. 8, 1958 3 Sheets-Sheet 1 l lNvi-:NroR @md a BY July 7, 1942. E. A. RocKwELL VALVE DEVICE original Filed Nov. 8, 1938 s sheets-sheet 2 July 7, 1942. E. A. RocKWELL VALVE DEVICE Original Filed Nov. 8, 1938 5 Sheets-Sheet 5 www@ um ,um mwN RMN wm w vm \K\ K\ .H .IHNMNNNIMHHHHI/ I um- IHHHMMII M /(\\U mv ma. f f Nm. um. am N Sw Sw Sm Y mm m WNN A 5ml?. QM NNN. www M .V w .QN I f NNN mm. u@ um /Mwwmi mw, Sw mm. mw. n @V m., NM. SN .x l @S SN N ,QM www mw Si NS. V, L @w @N K l K @Ng Wx N N NNN i INVENTOR AT ORNEY Patented July 7, 1942 VALVE DEVICE Edward A. Rockwell, Forest mils, N. Y., assigner to The New Britain Machine Company, New Britain, Conn., a corporation o! Connecticut original applicanonivovember s, 193s, semi No. f"

239,436. Divided and uns applleatlon neeember 1, 1939, Serial No. 307,117

19 Claims. (Cl. 121-465) My invention relates particularly to a valve device which is applicable to systems for the application of power for any desired purpose but also has especial application in connection with the operation of automotive accessories.

This is a divisional application of my application upon Power system, Ser. No. 239,436, filed November 8, 1938.

The object of my invention is to provide a valve device of general utility adapted to be used in a system for the application of power for any desired purpose, but it is especially useful in connection with the operation of automobiles and other automotive accessories. The said device is particularly adapted for use in a self-contained power unit which is capable of being mounted wherever desired upon an automobile or other automotive vehicle, inasmuch as the connections to the operating parts of the automotive struc-` ture are fully hydraulic, that is to say without the necessity of applying mechanical reaction members or devices between said unit and any accessory to be operated thereby. A further important object is the application of the same for the operation of brakes,'the same being conare moved into operative position manually initially, after which the power from said power unit is brought into action to apply the desired braking eiect to the wheels, thus eliminating the necessity of utilizing the high pressure hydraulic power except in the actual braking effort to be applied. This enables, furthermore, the braking eiort to be applied effectively, without requiring the movement of the foot pedal through substantially its entire available range of movement, as was previously required in other systems. Also, this avoids having to allow for lostmotion in lever and link connections. This permits the manual application of the braking effort in case of any failure of the application of power to the brakes. This also avoids lag in the relative movement of the parts. This arrangement is such, furthermore, as to permit the placement of the power unit at practically any point on an automobile chassis, which is of importance due to the limited space available in automobiles as now manufactured. It also enables the unit to be removed from danger of contact with road obstructions. In view of the said unit being provided with connections which are fully hydraulic, furthermore, the installation can be carried out in a very small fraction of the time that was required in the case of previous systems having mechanically operating connections thereto.

This enables, furthermore, the unit to be readily -serviced by merely removing -the unit and connecting a new power unit in its stead to the required tubular lines. The power unit is so constructed that it does not exert any thrust on the automotive parts on which it is mounted and will consequently retain its position when so mounted without danger of displacement or loosening, and even in the event of such loosenln ing or displacement, will continue to function nevertheless. The whole structure and installation can, therefore, be applied to automobiles with a very small fraction of the cost hitherto necessary in power units used for the operation of automobile accessories.

Further objects of my invention will appear from the detailed description of the Vsame hereinafter.

While my invention is capable of being carried out in many different ways, for the purpose of illustration I have shown certain embodiments of the same in the accompanying drawings, in whichl Fig. 1 is a diagrammatic perspective view of an automobile chassis equipped with my invenstructed in such a manner that the said brakes tion, as adapted to be operated by a vacuum;

Fig. 2 is a longitudinal vertical section of the power unit shown in Fig. 1 showing the position at the initial application of hydraulic pressure;

Fig. 3 is an end elevation of a casting contained within the outer casing taken from the lett end of Fig. 2;

Fig. 4 is a vertical section on line 4-4 of the same looking from the right towards the left of Fig. 2; and

Fig. 5 is a longitudinal vertical section of a modified form of my invention, in which compressed air is used instead of a vacuum, and showing diagrammatically the connections thereto.

Referring first to Figs. 1 to 4, I have shown an automobile chassis I having front wheels 2 and rear wheels 3 mounted on the chassis, hav' ing a rear axle I, by means of springs 5 and 6,

respectively, the same being connected to longiusual desired equipment. 0n the said chassis,

accessible to the driver, there is a foot pedal I2 carried by a pivot I3 on the chassis, which is connected by a link I4 to an operating lever I5 tight on a shaft I6 which extends into the interior oi' a master cylinder of any desired kind,

as, for example, a Loughead master cylinder I1, which may be constructed in accordance with the master cylinder shown in the Loughead et al. Patent No. 1,707,063, granted March 26, 1929. 'Ihe said shaft I6 operates an arm |8 within the master cylinder, which is adapted to move a piston |9 therein which operates in a cylinder having a hydraulic pressure fluid pipe connection 2|, which may be flexible. The master cylinderV I1 is mounted in any desired way, upon one of the frame members 9 of the chassis I. The said pipe 2l is connected by a fitting 22 to a casting 23 forming a part of a power unit 24 which is mounted on the automobile chassis I in any desired manner and at any desired point thereon but, for example, by means of U-shaped bolts 25 and 26 secured in place by nuts 21 on the frame member 1. Within the casting 23 there is a passageway 28 which is connected by a fitting 29 to a tube 30 attached by a tting 3| to a transverse passageway 32 which is located in a valve casing 33 screw-threaded to a cylindrical member 34, which in turn is screw-threaded also to the casting 23. Between the casing 33 and the cylinder 34 there is a rubber seal 34a which is U-shaped in cross-section and is supported on one face thereof by a washer 34h having serrations 34o at one face thereof, to permit the passage of liquid, the said seal 34a being supported at its other side by a ring 34d. The liquid from the master cylinder thus conveyed by the tube and the port 32 is received in a circular recess 35 in the valve casing 33, said recess having therein a serrated ring 36 having four serrations 31 thereon, said ring being supported within a U-shaped rubber seal 38 to provide a seal around a valve plunger 39, hereinafter described more in detail. On account of the serrations 31 the hydraulicv fluid is allowed to pass from the recess 35 into a passageway 40 in the casing 33 and thence through a tting 4| to a tube 42, a fitting 42a, and a tiny capillary opening 42b to prevent the actuation of the atmospheric inlet and outlet valve, hereinafter described, before the brake shoes have been moved into position, and thence to a pressure chamber 43 located in a casting 44 on the other end of the power unit, which is closed by a screw-plug 45 having an inner end 46 of reduced diameter through which there are four radial passageways 41 connecting to a longitudinal passageway 48 to act as a passage for the escape of any accumulated air from the hydraulic fluid. The passageway 48 is normally closed by means of a screwplug 49 having within the same a removable screw-threaded closure 50, upon the removal of which any accumulated air may be allowed to escape. The pressure chamber 43 thus permits manual pressure to be applied to a plunger 5I in the casting 44 in which it is sealed by an annular U-shaped rubber seal 52 held in place by a washer 53 and a snap-ring 54. The said plunger 5| is connected to a dished relief outlet valve or vacuum valve 55 in a vacuum chamber 56 in the casting 44, which is connected by passageways 56a and 56h to the exterior of said casting 44 and which is also connected by a longitudinal passageway 51 to a check-valve casing 58 having a check-valve 59 therein forced against its seat by a spring 60. Within the check-valve casing 58 there is a longitudinal passageway 6| communicating with lateral ports 62 which can be more or less closed and the tension of the spring on the valve 59 altered, as desired, by

a screw-threaded plug 63 within the said passageway 6| and which can be rotated by means of a squared extension 64 thereon fitting within a similar recess 65 in a rotatable adjusting member 66 carried within a screw-plug 61 in the check-valve casing 58, said rotatable member 66 having a pointer 68 cooperating with a graduated scale on the outside of the plug 61 and being held outwardly by means of a star-shaped spring 69. The ports 62 lead to a circular passageway 10 within a fitting 1| around the casing 58 and having a nipple 12 to which there is confil nected a iiexible hose 13 by means of a clip 14. The hose 13 leads to the engine manifold Ila. A spacing member 15 is provided around the check-valve casing 58 and a ilange 16 is provided on the screw-plug 45 to act as spacing members to hold in place an air lter casing 11 on the outside of said unit, having an air inlet opening 18 leading to a space 19 iilled with horsehair, and also for holding in place an end housing through which the plug 45 and the valve casing 58 extend. A gasket 8| is located between the end housing 80 and the casting 44. The air thus admitted to the chamber 19 passes through a screw-plug 82 in the casting 44 and thence into a passageway 83 in the casting 44, and passes through an opening 84 in a rubber diaphragm 85 and finally into an air chamber 86, on the opposite side of said diaphragm 85 from the location of the relief valve or vacuum valve 55. It will be noted that the said diaphragm 85 acts as a valve seat for the valve 55. On the same side` of the diaphragm 85 as the valve 55 there is a supporting ring 81a for limit- -ing the movement of said diaphragm in one direction and to act as a support for an air inlet valve 81 when said valve 81 is in closed position. against said diaphragm 85. There is also on the same side of the diaphragm 85 as the valve 81 a central ring 88, the outside diameter of which is slightly larger than the inside diameter of the ring 81a and on the opposite side of said diaphragm 85 there is a supporting ring 89, the rings 88 and 89 being held in place by a ferrule 90 and by a horseshoe washer 9|. The ferrule 90 is arranged to support one end of a spring 92, the other end of which passes through an extension 93 of the ferrule 90 leaving air ports 93a between the ferrule and theextension on which the valve 81 is mounted as well as a rubber diaphragm 94 and a ring 95, the same being held in place by a horseshoe-shaped washer 96. Attached to the casting 44 there is a spacing member 91 between the two diaphragms 85 and 94,

the same being held in place by a plurality of screws 98, which latter also support a cylinder 99 having a dished end provided with a plurality of holes |00 therein and acting as a support for one end of the spring 92. Said cylinder is located around the plunger 39, the latter being connected therein to a piston |0| which is comprised of two end plates |02 and |03 having located between the same a leather ring |04 which has a right-angle cross-section so as to t within the cylinder 99. Also, there is carried on the plunger 39, adjacent to the plate I 03, a retainer shell |05 for holding in place a felt ring |06 which acts as a peripheral support for the leather ring |04. A washer |01 is provided for holding these plates in place on the plunger 39 and around said plunger there is furthermore provided a light helical spring |08, one end of which abuts against the piston I 0| while the other end of which seats against a closure |09,

mounted on the valve housing 33, for said cylinvder 99, having openings to give access to the vacuum in which the cylinder 99 is submerged and surrounded. A cork packing is located around the plunger 39, held in place by a shell I I2 thereon. When the pressure in the pressure chamber 43, in the manner hereinafter described, causes the plunger 39 to be moved to the right, in Fig. 2, the said plunger 39 cuts oi access of the pressure uid from the tube 30 to the interior of the cylinder 34 so that further movement ofthe plunger 39 to the right forces the trapped liquid in the cylinder 34 out through a port ||3 and thence through a tting ||4 into a tube ||5, which is then conveyed by a, pipe system ||6 to four wheel cylinders ||1, all of which are constructed alike and each of which carries two pistons I8 and I9 for operating, respectively, brake shoes |20 and `|2|, which in this way apply the brakes to wheel drums |22 located on the wheels 2 and 3. In completing the power uni there is fastened onto one end of the unit a cover |23 by means of screws |24 on the casting 23 and a ring |25 is spun onto flanged edges of the cover |23 and the housing 80 so as to make a tight joint, thus submerging all the parts within same in a vacuum. For oiling purposes there is an inlet iitting |25a closed by a plug |25b and which is connected by a pipe |25c to the interior of the cylinder 99.

In the modification of my invention, as shown in Fig. 5, the construction of the apparatus is the same as in the preceding ligures except in the following respects: In this instance, instead of the source of vacuum there is provided a source of compressed air. Furthermore, the housing 80 and cover |23 are made strong enough to withstand whatever compressed air pressures' are used. Also, in this instance the apertures ||0 are omitted and an adequate breather tube |26 is connected from the tight closure |09 to the space 19. Furthermore, there is provided a source of compressed air |21 connected by a clip |28 to a nipple |29 having an annular passageway |30 through which passes a screw plug |3| having ports |32 leading to a ball check-valve |33 seated by a spring |34 so as to provide a body of compressed air within the housing 80 and cover |23.

y The compressed air thus supplied enters the valve structure through a port |35 in a spacing member |36 between'diaphragms |31 and |38 which are constructed like the diaphragms 85 and 94. The exhaust air in this instance, when escaping from the valve 55, passes out through a passageway |39 in a casting |40, which is in other respects constructed like the casting 44, so that said air reaches the space 19 in communication with the outer air. Also ports 56a and 55h are omitted.

In the operation of my invention, referring first to Figs. 1 to 4, the engine I0 being in operation and the vacuum being thus available through the pipe 13, the same is conveyed to the vacuum chamber 56 of the power unit 24 and thence through the passageways 66a and 56h so as to submerge all the parts -in the housing 80 in the vacuum by way of the passageway 51, chamber 56, passageways 56a and 56h to the inside of the housing 80 and cover |23. Also, the vacuum will extend from beneath the valve 55, which has no force seating it, through the ferrule 90 to the left face of the piston |0|. When the pedal |2 is pressed downwardly to the extent desired, by the foot, the lever arm |8 Within the master cylinder |1 moves the piston |9 to force vacuum beneath the valve 55 and the atmospheric inlet valve 81 will have remained closed due to the atmospheric air pressure in the closed position of the valve 81, entering through the port 84 and exerting nearly the same fluid force to seat the valve 81 as the fluid force to unseat said valve 81 and the spring 92 aiding in forcing the seating of the valve 81 on the diaphragm 85 on the other side of which there is a vacuum.

which seating remains tight due to the slight iiexing of the diaphragm` 85, as shown by the clearance between the plate 88 and the diaphragm 85 in Fig. 2 of the drawings. When further pressure, however, is exerted from the foot pedal |2 the pressure, which up to this point is received by the tube 42 and the pressure chamber 43 will have been insufficient to move the diaphragm 85 to unseat the atmospheric inlet valve 81, will now push the valve 81 01T its seat in opposition to the force of the spring 92, as the diaphragm 85 will then be flexed further to the right and the ferrule 90, 93 will also be moved to the right, thus simultaneously closing by tightly seating the valve 55 and moving the plunger 39 to the right in Fig. 2 so as to seal the chamber within the cylinder 34 by reason of the seal 34a. The said plunger 39 is, therefore,` now moved initially due to the manual pressure from the liquid in lthe tube 42 but as to in any event permit the manual application of the manual pressure on the brakes through the pipe 30, cylinder 34 and pipe ||5 in case there should be any failure of the power from the operation of the power unit. However, in the normal operation of the apparatus at this point, due to the seating of the valve 55 and the unseating of the valve 81, the pressure of the atmospheric air entering through the passageways 18 and 83 and air chamber 86 will pass through the ports 93a in the ferrule 93 and the openings |00 to the face of the piston |0| so as to force the same to the right in Fig. 2, in view of the vacuum which is present on the other side of said piston, and, owing to the very large diameter of the piston |0| as compared to the diameter of the plunger 39, the very low manual force applied, as, for example, 50 to 400 lbs. per square inch, will be supplanted by a pressure up to but not exceeding 1200 lbs. per square inch in the tube I|5 supplying the liquid to the brake cylinders ||1. This maximum pressure to be obtained can be deter-I mined by the adjustment of the rotatable vacuum adjuster 66, and if, due to wear in the automobile, the maximum obtained is less than said maximum, the vacuum can be adjusted again by the rotatable adjuster 66 to provide a more efl'ective vacuum due to the changed tension in the spring 60. It will be noted also that the diaphragm supporting plates 88 and 95 and the peripheral supports of said diaphragms are, respectively, of the same size so that the effective areas of each diaphragm, that is to say the portion subjected to the differential between the two pressures on opposite sides thereof, is ap- -brought to bear upon the brake-shoes |20 and |2| according to the degree of the low manual pressure exerted. However, very little brake fluid will have been used or needed to be brought into motion to bring about the braking action, as the brake-shoes will have already been brought previously into position before the braking action by the manual force applying the liquid to the brake-shoes. Furthermore, it will be seen that this is accomplished by a very small degree of movement of the foot pedal as very little motion is required to bring the brake shoes into operative position and substantially all of the subsequent effort is merely the exertion of the manual pressure with extremely little movement of the hydraulic fluid leading to the brakeshoes. In other words, the great disadvantage ofV previous hydraulic systems of requiring the foot to move through an extensive range with consequent danger of ineifectiveness, especially when used with boosters, is obviated. Upon the release of the pressure from the foot pedal |2 the spring 92 extends to close the valve 81 and the valve 5,5 opens so that air from within the left end of the cylinder 99 is exhausted, due to the vacuum in the pipe 13, and therefore the plunger 39 moves to the left, in Fig. 2, until the seal 34a is uncovered, thereby permitting the escape of any possible excess of the liquid which has been trapped beyond the end of the plunger 39 and releasing the brakes, so that the parts for operating the brakes are again in position for action whenever the brakes are to be applied, as previously described. In the event that the power unit should fail to operate, the brakes may still be applied manually by forcing the hydraulic fluid from the pipe 2| through the pipe 30, around the right-hand end of the plunger 39 into the chamber 34, and thence to the brake cylinders ||1 through the pipes ||5 and lli.

The operation of the modification shown in Fig. 5 is substantially the same as in the form of my invention in the preceding figures except in this instance air pressure takes the place of the atmospheric pressure on the left face of the piston the other face of said piston being in communication with the outer air through the breather tube |26. In this instance, after the brake shoes have been moved into position initially by the hydraulic fluid through the pipes 30 and ||5 the further pressure of the same acting onthe plunger tightly closes the valve 55 and causes the valve 81 to open because the diaphragm 85 is then further bowed to the right and the valve pushed off its seat by the ferrule 90, 93, thus admitting compressed air through said ferrule to the left face of the piston |0| which causes the latter to move to the right. The plunger 39 is then moved to the right, cutting ofi the communication between the pipe 30 and the passageway in the cylindrical member 34 and applying the high pressure in the liquid trapped therein to the brake-shoes |20, |2| on the four wheel brakes, depending upon the amount of the modulated pressure applied by the foot to the pedal |2. Upon the release of the foot pressure in the off-modulation the braking en'ect can be released as much as desired until finally upon the While I have described my invention above in detail I wish it to be understood that many changes may be made therein without departing from the spirit of the same.

I claim:

1. A valve structure having a. connection for receiving a pressure dinering from the atmospheric pressure, comprising a flexible diaphragm, an inlet valve and an outlet valve adapted to seat against opposite sides of the diaphragm and manual means connected to close the outlet valve and, with the movement of the diaphragm, to open the inlet valve.

2.A valve structure having a connection for receiving pressure diii'ering from the atmospheric pressure, comprising a diaphragm, an inlet valve and an outlet valve adapted to seat thereon, and another diaphragm on which one of said valves is mounted.

3. A valve structure having a connection for receiving pressure differing from the atmospheric pressure, comprising a diaphragm, an inlet valve and an outlet valve adapted to seat thereon, and diaphragm supporting means on opposite sides of said diaphragm, opposite to which said inlet and outlet valves seat, respectively, adapted to prevent the diaphragm from moving in either direction beyond a predetermined position.

4. A valve structure having a connection for receiving pressure differing from the atmospheric pressure, comprising a diaphragm, an inlet valve and an outlet valve adapted to seat thereon, and diaphragm supporting rings on opposite sides of said diaphragm, opposite to which said inlet and outlet valves seat, respectively, adapted to prevent the diaphragm from moving in either direction beyond a predetermined position in the seating of the inlet valve.

5. A valve structure comprising a flexible diaphragm, a valve adapted to seat against one side of said diaphragm, means adapted to ex the diaphragm into a bowed position adjacent to the point where said valve is seated, and a second valve adapted to seat against the iiexed portion of the diaphragm on the other side of the diaphragm.

6. A valve structure having a connection for receiving pressure diiering from the atmospheric pressure, comprising a diaphragm, an inlet valve and an outlet valve adapted to seat thereon, a second diaphragm on which the inlet valve is carried, a plate for limiting the flexing of the second diaphragm, and a plate for limiting the flexing of the first diaphragm, the said plates being of substantially the same diameter.

7. A valve structure having a connection for receiving pressure differing from the atmospheric pressure, comprising a diaphragm, an inlet valve and an outlet valve adapted to seat thereon, a second diaphragm on which the inlet valve is carried, a plate for limiting the flexing of the second diaphragm, a plate for limiting the flexing of the iirst diaphragm, and a rigid means connecting the said diaphragms, plates and inlet valve together.

8. A valve structure comprising a diaphragm adapted to act as a valve seat, a normally open valve adapted to seat thereon, a normally closed to their initial positions.

valve adapted to seat also on said diaphragm, a second diaphragm on which the normally closed valve is supported, and means to operate said valve for the performance of work, including means to normally apply a pressure differing from the atmospheric pressure between the normally closed valve and the first mentioned dlaphragm and to one side of the second diaphragm and another pressure differing from the firstmentioned pressure between the normally closed valve and the other side of said second diaphragm.

9. A valve structure comprising a diaphragm adapted to act as a valve seat, a normally open valve adapted to seat thereon, a normally closed valve adapted to seat also on said diaphragm, a second diaphragm on which the normally closed valve is supported, and means to operate said valve for the performance of work, including means to normally apply a pressure differing from the atmospheric pressure between the normally closed valve and the first mentioned diaphragm and to one side of the second diaphragm and another pressure differing from the firstmentioned pressure between the normally closed valve and the other side of said second diaphragm, the effective areas of each of said two diaphragms exposed to the differential of said first and second pressures being approximately the same.

10. A valve structure having a connection for receiving pressure differing from the atmospheric pressure, comprising a diaphragm, an inlet valve and an outlet valve being adapted to seat thereon, one of said valves being smaller than the other, supports on the opposite sides of said diaphragm to support said valves respec tively, the said supports being overlapping at the outer periphery of the outlet valve support and the inner periphery of the inlet valve support.

l1. A valve structure comprising a first diaphragm, a second diaphragm, a casing on which they are supported, having a port giving access for a fluid to the first diaphragm, a manually operable valve seating on said first diaphragm, a second valve seating on the other side of said diaphragm and supported bysaid second diaphragm, and means for clamping said two diaphragms to said casing in spaced relationship, providing a port giving access to a fluid of another pressure intermittently to a side of said second valve normally inaccessible to said other pressure so as to control the application of said second pressure by said second valve for the performance of work.

12. A valve structure comprising a first diaphragm, a second diaphragm, a casing on which they are supported, having a port giving access for a uid to the flrst diaphragm, a manually operable valve seating on said first diaphragm, a second valve seating on the other side of said diaphragm and supported by said second diaphragm, means for clamping said two diaphragms to said casing in spaced relationship, providing a port giving access to a fluid of another pressure intermittently to a side of said second valve normally inaccessible to said other pressure so as to control the application of said second pressure by said second valve for the performance of work, and a rigid connecting means between the said two diaphragms having a passageway providing a communication between the inner and outer faces oi' both diaphragms.

13. A valve structure comprising a first /diaphragm, a second diaphragm, a casing on which they are supported, having a port giving cess for a fluid to the rst diaphragm, a manually operable valve seating on said first diaphragm, a second valve seating on the other side of said diaphragm and supported by said second diaphragm, means for clamping said two dia- 75 5 pressure so as to control the application of said second pressure by said second valve for the performance of work, and a rigid connecting means between the said two diaphragms having a passageway providing a communication between l the inner and outer faces of both diaphragms and a spring in said passageway adapted to be compressed upon unseating the second valve.

14. A valve structure comprising a first diaphragm, a second diaphragm, a casing on which l they are supported, having a port giving access for a fluid under sub-atmospheric pressure to the first diaphragm, a manually operable valve seating on said first diaphragm, a second valve seating on the other side of said diaphragm and supported by said second diaphragm, and means for clamping said two diaphragms to said casing in spaced relationship, providing a port giving access to a fluid under atmospheric pressure intermittently to a side of said second valve normally .25 inaccessible to said other pressure so as to control the application of said second pressure by said second valve for the performance of work.

15. A valve structure comprising a first diaphragm, a second diaphragm, a casing on which they are supported, having a port giving access for a fluid under atmospheric pressure to the first diaphragm, a manually operable valve seating on said first diaphragm, a second valve seating on the other side of said diaphragm and sup- :15 ported by said second diaphragm, and means for clamping said two diaphragms to said casing in spaced relationship, providing a port giving access to a fluid under superatmospheric pressure intermittently to a side of said second valve nor- :n mally inaccessible to said other pressure so as to control the application of said second pressure by said second valve for the performance of work.

16. A valve structure, comprising a diaphragm,

4:, a uid pressure controlling valve adapted to seat thereon, a second fluid pressure controlling valve connected to and movable with said diaphragm, and means to apply normally in the closed position of the second valve very nearly the same so fluid force in one direction tending to seat said second valve as the fluid force in the opposite direction tending to unseat the said second valve.

17. A valve structure, comprising a diaphragm, a valve adapted to seat thereon, a second valve connected to said diaphragm, means to apply normally very nearly the same force in one direction tending to seat said second valve as the force in the opposite direction tending to unseat said second valve, and a second diaphragm on which said second valve is mounted.

18. A valve structure, comprising an outlet valve, a diaphragm on which it seats, a second diaphragm, an inlet valve rigidly connected to both of said diaphragms, and a housing for said diaphragms having inlet and outlet ports for pressure iiuid.

19. A valve structure, comprising an outlet valve, a diaphragm on which it seats, a second ,diaphragm an inlet valve rigidly connected to both of said diaphragms, a housing for said diaphragms having inlet and outlet ports for a pressure fluid, a plate connected to said housing, and a spring, adapted to move said diaphragm, seated on said plate.

EDWARD A, ROCKWELL. 

